Big passengers should ask about seat policies before flight

Each airline has its own guidelines on whether overweight passengers should buy more than one seat and how much it costs.

With that angry Twitter post and a slew of unprintable other tweets and blog posts, indie film director Kevin Smith earlier this month renewed a big, fat controversy over how airlines should handle passengers who can't squeeze into a coach seat.

Smith unleashed his cyber-invectives after Southwest Airlines removed him from an Oakland-Burbank flight he had boarded on standby. Southwest said it acted because the sizable Smith required two seats and there wasn't an extra seat. Smith said he fit into a single seat.

Regardless of who was right in Smith's case, two things are clear: Southwest isn't unusual in requiring two seats for some larger passengers. And as debt-ridden airlines pack more people onto planes, spare seats are getting scarce, leading to conflicts. Last year, the average domestic flight filled 81% of its seats, a record for the decade.

"As flights began to be fuller, there was an uptick in complaints…from folks who had to share their seat with somebody else," said Robin Urbanski, spokeswoman for United Airlines. By spring 2009, United had fielded 700 such complaints within a year, she added.

United and several other carriers responded by updating their policies on "customers of size" and "passengers requiring extra space." Here's what to ask if you think you might be affected:

How big is too big? That depends on the airline, and it's open to interpretation.

Southwest says you should book a second seat if you are unable to lower both armrests or if you "compromise any portion of adjacent seating." American and United use three tests: inability to fit into a single seat, put the armrests down or properly buckle the seatbelt with a seatbelt extender.

Delta Air Lines doesn't list its criteria. Instead, "we allow our employees some latitude in making decisions based on the safety of a flight and the best interests of the passenger," spokeswoman Susan Elliott said.

What does a second seat cost? Maybe a lot or maybe nothing.

At Southwest, if you book two seats at the same time under its discounted "advance purchase" fares, both cost the same. But if you book a "Business Select" or "Anytime" fare for the first seat, you get the second seat at a cheaper child's fare. In either case, if the flight is not oversold, you can later apply for a refund of the second fare. Alaska Airlines also offers refunds.

American and United don't generally offer refunds or discounts for second seats in this case. But if you show up for a flight ticketed for a single seat and a second seat is needed, both airlines say they will give it to you for free if there's room. If not, your options include trying to get on the next flight or paying for an upgrade to a cabin that may have an extra seat.

At Continental, like American and United, your first and second seats cost the same if bought in advance. But if you show up for your flight with a ticket for a single seat and the staff determines you need a second one, you'll be charged "the lowest fare available for purchase at that time," spokeswoman Mary Clark said. Depending on the flight, that fare could cost hundreds more than what you paid for the first seat.

Can I take more bags? Not necessarily. Your carry-on allowance, which is set per passenger by the government, doesn't change.

As for checked bags, United, which charges $25 each way for the first bag and $35 for the second, applies its allowance to each seat. So if you book two seats and check two bags, your fees will total $50 instead of $60. Delta Air Lines has a similar policy. But Southwest, which doesn't charge for the first two bags, says that whether you occupy one or two seats, you can take only two bags for free.

What about change fees? Continental, Delta and United charge them per seat, so with two seats you'll pay twice as much to change your flight plans. Alaska Airlines also charges only one fee in this situation. (Southwest generally doesn't charge change fees.)

Will I get double frequent-flier miles? Not on Southwest. But on Alaska, Continental, Delta and United, you'll earn miles for each seat ticketed in your name.